FLOOD05261

• Designation Number: 555
• County: Adams
• County: Denver
• Community: Denver
• Stream Name: Lower Box Elder Creek Watershed
• Basin: South Platte
• Title: FHAD - Lower Box Elder Creek Watershed
• Date: 9/1/2001
• Prepared For: Denver, Adams County
• Prepared By: Wright Water Engineers, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

Flood Hazard Area Delineation
For Lower Box Elder Creek Watershed

TABLE OF CONTENTS

Section

1.0
U
12
1.3
1.4
1.5

INTRODUCTION ....................................................................................
Authorization. c c.. .cc ... ..... cc..... c c... cc. c c c. c. cc c c cc cc c c c cc ..c cc cc c...c... .... c. .......... c. c... c. c.
Purpose c c cu... c u. cu c.. u.. c uc c. ...uu.u U c. u u.. U uu C'" c. 'u. c c uu.. .c. c.... u U c...u c. u....
Scope .c c...c... .cc C"Cc c cccc c. ..cc.... c.... ... ..... c.. c. c. c. c. c. c. c.. c.. c. cccc c..c cc .... .... c. .... c.. u.. c
Mapping.. c... "cc','u. ... c c.. cu. .c. cc ccc ccc. c... c........ c.......... c.. ..c.. c.. c. ... c ..c. cc c c cc.c. c c.. c
Sponsors and Stakeholdersu c.. cc u u u c.. u c c cc cc c. c.. c c. Cu..u c..u... u.... c. c. c..... c. u c

2.0
2c1
22
2c3
2A
2A1
2.42
2A3
2.5

STUDY AREA DESCRiPTION...............................................................

Topography. ..c.. ..c. ... cc. c.ccc.c cc. c. ccc c...... c............... c... c. c c.... c.. c.. c c... c. c. cc cc cc c c c.c
Watershed Imperviousness ... cu c... c. u. u c. u u u u u c u u.. uu...... U u.. c.. u. u. u. U c.

Soils . ..... c. uc c..... .u... uu c we c uc u u. c. U U u.. c... u.. c... u.. c. c....... u. c u uc cuc.u u.... u..
Surface Waler Resources c uC c. U cu.... U .... c. c... c... c.. c', c. uu ......u cc cc c. u.c u cc......
Stream Characteristics. c u.. ... c u. uc c c u u cc..u.c cc.. u... ..... uu. u. C' u.... u u u u u u c cu
Reservoirs .... c. c.. U c.' ..... cc. c.c c cc..c ccc c.c c c c cc c..c.. cc. c... c.. c c.. ..c c.... c.. c.. ... c c. c.c. c c. c. c. c
Diversions ..... u c......... u...u... U u... u u u u u c cue u.u c. u c c cc. cue. c. u.... U U U c. U c. U u.. c
Flood History cc c c. cccc. c.. c. cccc. c. c... c... c.. c.... c. c. c... C' c. c. c.. c c. ..ccc. c c.c cc c. .... ........... c. c.

3.0
3.1
32
3c3
3A
3c5
3c6
3.7

BASELINE HYDROLOGIC ANALYSIS .................................................

Hydrologic Models... u. ..... .uu .uc u u cc u .c. c.c u.. c. c.... u... u... c...... u u u u u u u u u u
Watershed Description .u c. c', c c u u. u c c u u u u u c c cc u c. c .c... uu ....... c.. .... c..... c. c u u c
Rainfallccc ccccc c.cc. cc cc.cc c... ...... c. c.... c... c.... "c. c. c. c. c. c. c.. cc.c. .Cc ........ c. c. ..... .... C" c....
CUHP Modeling. u u. u... u... U c.... u.. u..u. u u.. cu c c u.c u.....u. u. u. u.. ...u. U C' c... c..
UDSWM Modeling c c..... cu... c U u. u.. C' C' c. c.. ..... u c. u u.. u.uu c u u uc c.. u.. u.. u.......
Resultsu c c Uu. c c c ...u.. u. c. cue... cu. u.. c. c. c. u u u u.. u u u uc cu..u... c u........ ..... cu. c u. c.
Comparison With Previous Studies ....u.....uuu.c.cuuu..uuuuc..u..............

4.0
4c1
42

HYDRAULIC ANALYSIS ......................................................................
Methodology .cc.. ...... C'" "cc" c.. c. ... c..c c. c. cc cc cc cc c. cc c.... c.... .u. ....... c..... C" ... c.. ... c. c
Resultscc... c c. c c... c...... c .c. ...... ....... C'" C" ... c c... ........ c.. ...c .ccc. c cc. c. c.c c. c. c. c..... c..... c

5.0 REFERENCES .......................................................................................

Paae
1
1
1
1
1
1
2
2
2
3
3
3
3
4
4
5
5
5
5
6
6
7
7
Table No.
8
8 3-1
9
9 3-2
3-3
3-4
4-1

APPENDICES

Appendix A-Study Area
Appendix B-Sub-Watershed Delineation
Appendix C-Hydrologic Soil Grouping
Appendix D-Existing Percentage Imperviousness
Appendix E-Future Percentage Imperviousness
Appendix F-Rainfall
Appendix G-CUHP Input Parameters
Appendix H-UDSWM95 Conveyance Elements
Appendix I-UDSWM95 Connectivity Diagrams
Appendix J-UDSWM95 Input Parameters
Appendix K-Hydrographs at Upstream Study Area Boundary
Appendix L-Peak Discharges
Appendix M-Hydrographs at Selected Locations
Appendix N-Peak Discharge Versus Stream Station
Appendix O-Comparison With Previous Studies
Appendix P-Floodplain and Floodway Data
Appendix Q-Floodplain Delineation Plans
Appendix R-Floodplain Profiles
Appendix S- Typical Stream Cross Sections

LIST OF TABLES

Paae

Summary of Watershed Delineation ............u....uuc.u..u.u........c.u.u.uucc

5

Rainfall Point Precipitation u......u.u.u.uu..uuuuu.uucuu.Uuu.....u..uuu.u.. 5

Summary of Precipitation Area Adjustmentsuu...uu.u...u..uu...........u...u 6

Summary of Peak Flow for Selected Locations u.uu..........u.uu.uccu.u..u 7
Summary of Floodplain and Floodway Widh...cuuuu...u.u..uuu.uc......... 9

99l-134cOOO

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Wright Water Engineers, Inc.